hrvatski

HIDROGEOLOŠKA ISTRAŽIVANJA KRŠKIH TOKOVA VODE U PODZEMLJU SJEVERNOG VELEBITA.

First published hydrogeological studies on ground water flow through the North Velebit Mt. karst massif, which spread among sinking zones of Lika and Gacka rivers on the east and Velebit channel on the west, date back at the beginning of the 20th century (Schenkel, 1912 ; Terzaghi, 1913 ; Koch, 1925/26). Since the mid- 20th century a number of tracing tests on the Lika and Gacka rivers main sinkholes were performed. Results of the tracing tests proved existence of exceptionally complex and branched karst conduit systems in the massif (Biondić i Goatti, 1976 ; Kuhta et al., 2010 ; Stroj et al., 2010). System complexity reflects in a very wide outflow area, which extends from Novljanska Žrnovnica springs (south of Novi Vinodolski town) on the north to Karlobag town on the south (Fig. 1). The outflow area overlapping the Gacka and Lika rivers sinking waters, as well as Brinje karst polje sinking streams, was also confirmed. This points to widespread occurrence of ground water flow bifurcations, and dominantly pipe hydraulics of water flow. Speleological explorations of the deep pits in the massif enabled direct study of water flows deep beneath the surface. Observation of the syphon at the bottom of Lukina jama Cave, established during expeditions in 2010 and 2011, provided insight into dynamics of ground water in the central parts of the karst massif (Fig. 2). Research carried out in other deep pits was focused on the vadose flows characteristics in the massif. Study of ground water level in sinkhole caves and nearby boreholes determined the basic features of the water dynamics in the area of the eastern foothills of the North Velebit Mt. (Stroj, 2010 ; 2013), while the research of coastal springs provide insight into mechanisms of salt and fresh water mixing in the coastal karst aquifer (Stroj, 2010 ). Despite relatively extensive research that has been conducted so far, the karst system in the North Velebit Mt. underground is still largely unknown, which leaves room for future research.

hidrogeologija, trasiranja, speleologija, Sjeverni Velebit

nije evidentirano